Commit 9094db4b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipmr: do not acquire mrt_lock before calling ipmr_cache_unresolved() 



rcu_read_lock() protection is good enough.

ipmr_cache_unresolved() uses a dedicated spinlock (mfc_unres_lock)

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 559260fd

net/ipv4/ipmr.c

+8 −17
Original line number Diff line number Diff line
@@ -680,7 +680,7 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, 
			if (VIF_EXISTS(mrt, tmp))

				break;

		}

		mrt->maxvif = tmp+1;

		WRITE_ONCE(mrt->maxvif, tmp + 1);

	}



	write_unlock_bh(&mrt_lock);
@@ -905,7 +905,7 @@ static int vif_add(struct net *net, struct mr_table *mrt, 
		WRITE_ONCE(mrt->mroute_reg_vif_num, vifi);

	}

	if (vifi+1 > mrt->maxvif)

		mrt->maxvif = vifi+1;

		WRITE_ONCE(mrt->maxvif, vifi + 1);

	write_unlock_bh(&mrt_lock);

	call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev,

				      vifi, mrt->id);
@@ -1923,11 +1923,12 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt, 
	kfree_skb(skb);

}



static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev)

/* Called with mrt_lock or rcu_read_lock() */

static int ipmr_find_vif(const struct mr_table *mrt, struct net_device *dev)

{

	int ct;



	for (ct = mrt->maxvif-1; ct >= 0; ct--) {

	/* Pairs with WRITE_ONCE() in vif_delete()/vif_add() */

	for (ct = READ_ONCE(mrt->maxvif) - 1; ct >= 0; ct--) {

		if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)

			break;

	}
@@ -2161,15 +2162,9 @@ int ip_mr_input(struct sk_buff *skb) 
			skb = skb2;

		}



		read_lock(&mrt_lock);

		vif = ipmr_find_vif(mrt, dev);

		if (vif >= 0) {

			int err2 = ipmr_cache_unresolved(mrt, vif, skb, dev);

			read_unlock(&mrt_lock);



			return err2;

		}

		read_unlock(&mrt_lock);

		if (vif >= 0)

			return ipmr_cache_unresolved(mrt, vif, skb, dev);

		kfree_skb(skb);

		return -ENODEV;

	}
@@ -2273,18 +2268,15 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb, 
		int vif = -1;



		dev = skb->dev;

		read_lock(&mrt_lock);

		if (dev)

			vif = ipmr_find_vif(mrt, dev);

		if (vif < 0) {

			read_unlock(&mrt_lock);

			rcu_read_unlock();

			return -ENODEV;

		}



		skb2 = skb_realloc_headroom(skb, sizeof(struct iphdr));

		if (!skb2) {

			read_unlock(&mrt_lock);

			rcu_read_unlock();

			return -ENOMEM;

		}
@@ -2298,7 +2290,6 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb, 
		iph->daddr = daddr;

		iph->version = 0;

		err = ipmr_cache_unresolved(mrt, vif, skb2, dev);

		read_unlock(&mrt_lock);

		rcu_read_unlock();

		return err;

	}